Shifting shoreline of the estuarine landscape in the East Godavari district of Andhra Pradesh, India

Shorelines act as indicators of coastal changes and help in assessing the effect of changing sea levels and river runoff on the shore. The East Godavari River Estuarine Ecosystem (EGREE) in Andhra Pradesh, India is an ecologically significant landscape and is host to the second largest contiguous mangrove forests in India. At the same time, it is also an upcoming complex for industrial developments. The rapid economic development of this coast makes it necessary to investigate the erosion and accretion of its shoreline so that decision-makers can be better informed. A temporal dataset of the shorelines in this coast between 1977 and 2015 was generated using visual interpretation of Landsat suite of satellite data. The shorelines could be generated with an annualised error of +/- 2.86 m/year. Digital Shoreline Analysis System (DSAS), a widely used tool to understand the behaviour of the shoreline, was used for estimating the erosion and accretion rates along different segments of the shoreline in EGREE. Based on the End Point Rate (EPR) statistic estimated through DSAS, the coastline was found to have eroded at a cumulative rate of 3.9 m/year between 1977 and 2015. The overall mean Linear Regression Rate (LRR) was found to be - 1.6 m/year. The erosional LRR was 9.8 m/year (LR2 = 0.68) and the accretional LRR was 8.2 m/year (LR2 = 0.69). The stretch between the mouth of Nilarevu distributary and Masanitippa was found to be the most dynamic stretch. Management decisions must take cognisance of the erosivity of the coast before burdening the coast with heavy developmental projects.